Lead-poisoning threat to unborn subject of study

Press, 13 May 1987, Page 55

Lead-poisoning threat to unborn subject of study

NZPA-Reuter Boston Pregnant women exposed to much less than the legal limits of lead may still poison their unborn children, medical researchers have said. In a far-reaching study published in the “New England Journal of Medicine,” scientists from Massachusetts and Pennsylvania concluded that the foetus might be adversely affected at blood-lead concentrations well below the United States Federal limit of 25 microgrammes per decilitre of blood. Lead can enter the bloodstream through the inhalation of air polluted by leaded petrol exhaust or the ingestion of dust created as leaded paint wears away. In tests of 249 children

studied between birth and age two, the researchers said they discovered that children born with lead levels of 10 microgrammes per decilitre of blood or more scored nearly 7 per cent lower on developmental tests than children with little or no lead in their blood. The researchers said that 40 per cent of United States children under the age of five have lead levels higher than 20 microgrammes. Dr David Bellinger, a neurologist at Children’s Hospital in Boston and the leader of the study team, said the results indicated that children not only needed to be kept away from lead after birth but that high lead levels in pregnant women might cause lead poisoning in

their children. While past research has tended to centre on children living in poverty, the new study primarily involved middle-class or upper-class families. “The women (in the study) didn’t have levels very different from typical women living in cities,” Dr Bellinger said. He said it might also be possible that the hormonal changes that occur during pregnancy might unlock lead stored in the bones, which would allow it to reach the foetus. “We all carry about 100 to 500 times the amount of lead in our bodies than mankind evolved with because of bur urban environment,” - Dr Bellinger said. “The background level of exposure is so high, it —

doesn’t take much of an extra exposure to raise the blood level of an adult or child to levels where toxic effects are discernible.”

Pregnant women, he said, often decorate rooms planned as nurseries but they should avoid all exposure to lead and should not help strip old paint that might produce leaded dust.

Dr Bellinger said his research , did not determine whether the children studied outgrew the effects of the lead poisoning by the time they entered school.

“It is a warning sign that we ought to consider foetal exposure to lead to be a potential problem at levels we didn’t think would be a problem previously,” Dr Bellinger said.